3 papers
math.FA2026
Complete functional calculus bounds for -contractions
Michael Hartz, Jens de Vries
Let be a -contraction on a Hilbert space. We establish sharp bounds for the functional calculus of for matrix-valued analytic functions on the unit disc. These are compl…
math.FA2026
On the Schur-Agler Norm
Michael Hartz, Yi Wang
We establish a new description of the Schur-Agler norm of a holomorphic function on the polydisc as the solution of a convex optimization problem. Consequences of this description…
math.FA2024
Potential theory and boundary behavior in the Drury-Arveson space
Nikolaos Chalmoukis, Michael Hartz
We develop a notion of capacity for the Drury-Arveson space of holomorphic functions on the Euclidean unit ball. We show that every function in has a non-tangential…